The purpose of this study was to review the newest literature linking non-alcohoilc fatty liver disease(NAFLD), obesity, insulin resistance and physical activity, finally to provide guideline for future investigation. Recent data suggest that NAFLD correlates with obesity and metabolic disorders including insulin resistance. And exercise or lifestyle modification reduces the liver enzyme such as ALT, AST and GGT. Thus, physical activity should be strongly emphasised in both prevention and treatment to NAFLD. Futher studies will be needed to know mechanism of relationship between NAFLD and physical activity.